2,839 research outputs found

    Kondo effect in a quantum dot embedded between topological superconductors

    Full text link
    In this article, we study the quantum transport through a single-level quantum-dot in Kondo regime, coupled to current leads and embedded between two one-dimensional topological superconductors, each hosting Majorana zero modes at their ends. The Kondo effect in the quantum dot is modeled by mean-field finite-UU auxiliary bosons approximation and solved by using the non-equilibrium Green's function approach. First, we calculate the density of states of the quantum dot, and then both the current and the differential conductance through the quantum dot in order to characterize the interplay between the Kondo resonance and Majorana zero modes. The results reveal that the presence of Majorana zero modes modifies the Kondo resonance exhibiting an anti-resonance structure in the density of states, leading to obtain spin-resolved behavior of the measurable current and differential conductance. We believe our findings could be helpful to understand the behavior of the Kondo effect in connection with Majorana zero modes.Comment: 10 pages, 6 figure

    Ambivalence in How to Address Adolescent Marijuana Use Among School-Based Health Center Providers

    Get PDF
    Objective: As part of a larger study to evaluate the implementation of Screening, Brief Intervention, and Referral to Treatment (SBIRT) at school-based health centers (SBHCs), we interviewed SBHC providers regarding their perceptions of substance use among adolescents seen at their SBHCs, experiences providing care for students with substance use and other mental health issues, and their concerns around marijuana specifically. Methods: We interviewed 12 primary and behavioral health providers who worked at five SBHCs in New Mexico. The interviews lasted approximately 1 hour and were digitally recorded and professionally transcribed. Two research team members independently analyzed the transcripts. We undertook iterative comparative analysis of qualitative data specifically related to marijuana and substance use, coding segments of text on key sensitizing concepts. Results. Six key themes emerged from the provider interviews: (1) marijuana use is indicative of underlying mental health issues; (2) normalization of marijuana use; (3) hesitance to endorse marijuana as a medical treatment for youth; (4) risks of marijuana use relative to alcohol use; (5) tension between building trust with adolescent patients and asserting authority; and (6) knowledge and skills gaps that impact counseling. Conclusion: Our findings elucidate key domains to address to support providers in their efforts to increase the health and safety of adolescents in a state that is rapidly expanding legislation and acceptance of marijuana. These findings may benefit providers in states that are enacting policies favorable to marijuana use

    The impact of breeding Yellow-Legged Gulls on vegetation cover and plant composition of Grey Dune habitats

    Get PDF
    The establishment of large populations of yellow-legged gull Larus michahellis in coastal and urban areas can lead to strong changes in vegetation cover and composition through creating physical disturbance in the vegetation and impacting the soil quality through defecation. In this study, we evaluated the effects of breeding yellow-legged gull populations on tall and short vegetation cover and plant species composition in old (occupied for 13 years) and new (occupied for 3 years) colony sites in grey dunes of the Algarve, southern Portugal. In each site, sampling plots were used to measure the percentage of vegetation cover in areas with and without breeding gulls. In the old colony site, the cover by tall vegetation was substantially reduced and the cover by short vegetation substantially increased in the areas where gulls are breeding in comparison with the adjacent areas. In the new colony sites, there were only minor differences. The increase in cover of short vegetation in the breeding area of the old colony site was mostly by nitrophilous species (Paronychia argentea and Malcolmia littorea) and should be explained by the decrease in vegetation cover of tall plant species and by feces deposition. Tall and slow-growing species Suaeda maritima and Helichrysum italicum covers were negatively affected. Our results showed that yellow-legged gulls affected vegetation cover and composition of grey dunes after 3 years of consecutive breeding, and this should be considered in the management of these habitats where breeding yellow-legged gulls are increasing.info:eu-repo/semantics/publishedVersio

    Poor Cognitive Agility Conservation in Obese Aging People

    Get PDF
    Life expectancy has been boosted in recent decades at expenses of increasing the ageassociated diseases. Dementia, for its incidence, stands out among the pathologies associated with aging. The exacerbated cognitive deterioration disables people from carrying out their daily lives autonomously and this incidence increases exponentially after 65 years of age. The etiology of dementia is a miscellaneous combination of risk factors that restrain the quality of life of our elderly. In this sense, it has been established that some metabolic pathologies such as obesity and diabetes act as a risk factor for dementia development. In contrast, a high educational level, as well as moderate physical activity, have been shown to be protective factors against cognitive impairment and the development of dementia. In the present study, we have evaluated the metabolic composition of a population between 60–90 years old, mentally healthy and with high academic degrees. After assessing agility in mental state, we have established relationships between their cognitive abilities and their body composition. Our data support that excess body fat is associated with poorer maintenance of cognition, while higher percentages of muscle mass are associated with the best results in the cognitive tests.Junta de Andalucia European Commission P20-01061 P18-RT-3324 P20-01293 PECART-0096-2020Ministry of Science and Innovation, Spain (MICINN) Spanish Government PID2019-110960GB-I0

    Fungal Endophytes Enhance the Photoprotective Mechanisms and Photochemical Efficiency in the Antarctic Colobanthus quitensis (Kunth) Bartl. Exposed to UV-B Radiation

    Get PDF
    Antarctic plants have developed mechanisms to deal with one or more adverse factors which allow them to successfully survive such extreme environment. Certain effective mechanisms to face adverse stress factors can arise from the establishment of functional symbiosis with endophytic fungi. In this work, we explored the role of fungal endophytes on host plant performance under high level of UV-B radiation, a harmful factor known to damage structure and function of cell components. In order to unveil the underlying mechanisms, we characterized the expression of genes associated to UV-B photoreception, accumulation of key flavonoids, and physiological responses of Colobanthus quitensis plants with (E+) and without (E−) fungal endophytes, under contrasting levels of UV-B radiation. The deduced proteins of CqUVR8, CqHY5, and CqFLS share the characteristic domains and display high degrees of similarity with other corresponding proteins in plants. Endophyte symbiotic plants showed lower lipid peroxidation and higher photosynthesis efficiency under high UV-B radiation. In comparison with E−, E+ plants showed lower CqUVR8, CqHY5, and CqFLS transcript levels. The content of quercetin, a ROS-scavenger flavonoid, in leaves of E- plants exposed to high UV-B was almost 8-fold higher than that in E+ plants 48 h after treatment. Our results suggest that endophyte fungi minimize cell damage and boost physiological performance in the Antarctic plants increasing the tolerance to UV-B radiation. Fungal endophytes appear as fundamental biological partners for plants to cope with the highly damaging UV-B radiation of Antarctica.Fil: Barrera, Andrea. Universidad de Talca; ChileFil: Hereme, Rasme. Universidad de Talca; ChileFil: Ruiz Lara, Simon. Universidad de Talca; ChileFil: Larrondo, Luis. Pontificia Universidad Católica de Chile; ChileFil: Gundel, Pedro Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Pollmann, Stephan. Universidad Politécnica de Madrid; EspañaFil: Molina Montenegro, Marco A.. Universidad de Talca; ChileFil: Ramos, Patricio. Universidad de Talca; Chil

    The role of environmental influences in the complex relationship between borderline personality disorder and attention-deficit/hyperactivity disorder : review of recent findings

    Get PDF
    In recent years, the existence of possible developmental pathways from childhood Attention-Deficit/Hyperactivity Disorder (ADHD) to adult Borderline Personality Disorder (BPD) has been suggested. The existence of common genetic factors has been described but there is little evidence on the role of environmental factors in the possible transition from one disorder to another throughout life. The main goal of this work is to review the literature about the existing evidence on childhood traumas as factors that mediate the risk of developing BPD in children with ADHD. A literature search was conducted using PubMed, Science Direct and PsychInfo databases. Criteria included studies of BPD and ADHD relationships and childhood traumas as environmental influences from epidemiological or clinical samples. The review only identified 4 studies that matched the search criteria. All studies retrospectively analyzed childhood traumas, and adult patients with BPD, with or without comorbid ADHD, were the most frequently mentioned. The analyzed evidence reinforces the relationship between the number of childhood traumas and higher clinical severity. Three of these analyzed studies describe an increased the risk of children with ADHD who report emotional and sexual traumatic experiences to develop BPD in adulthood. The experience of traumatic childhood events, especially those of an emotional type, may have a mediating effect of an increased risk of developing adult BPD in childhood ADHD patients. However, to consider them as risk factors, more studies, and especially longitudinal studies, are necessary to clarify the probable transactional process between the two disorders. Evidence from these studies may be helpful to develop early intervention programs to reduce the functional impairment associated with the two disorders

    Galaxy and mass assembly (GAMA): The environmental impact on SFR and metallicity in galaxy groups

    Get PDF
    We present a study of the relationships and environmental dependencies between stellar mass, star formation rate, and gas metallicity for more than 700 galaxies in groups up to redshift 0.35 from the Galaxy And Mass Assembly (GAMA) survey. To identify the main drivers, our sample was analysed as a function of group-centric distance, projected galaxy number density, and stellar mass. By using control samples of more than 16 000 star-forming field galaxies and volume-limited samples, we find that the highest enhancement in SFR (0.3 dex) occurs in galaxies with the lowest local density. In contrast to previous work, our data show small enhancements of ∼0.1 dex in SFR for galaxies at the highest local densities or group-centric distances. Our data indicates quenching in SFR only for massive galaxies, suggesting that stellar mass might be the main driver of quenching processes for star forming galaxies. We can discard a morphological driven quenching, since the Sérsic index distribution for group and control galaxies are similar. The gas metallicity does not vary drastically. It increases ∼0.08 dex for galaxies at the highest local densities, and decreases for galaxies at the highest group-centric distances, in agreement with previous work. Altogether, the local density, rather than group-centric distance, shows the stronger impact in enhancing both, the SFR and gas metallicity. We applied the same methodology to galaxies from the IllustrisTNG simulations, and although we were able to reproduce the general observational trends, the differences between group and control samples only partially agree with the observations

    Electro-ozonizers: A new approach for an old problem

    Get PDF
    This work focuses on the electrochemical production of ozone and its use in the degradation of pollutants contained in wastewater. To do this, the production of ozone by two commercial electrochemical cells specially designed to produce ozone (manufactured by CONDIAS GmbH) is compared, as well as their performance in the treatment of a synthetic wastewater containing Clopyralid. This treatment is also evaluated with ozone supplied by a conventional ozone generator. Results demonstrate that polymer exchange membrane (PEM) electrolyzers can produce efficiently ozone, which is consumed in the degradation of pollutants, although other oxidative pathways develop simultaneously, being co-responsible of the high efficiencies obtained. In comparing results, it was found a lower consumption of electrical energy in the production of ozone and a higher degradation and mineralization with electrochemical cells. A high percentage of the ozone produced by the electrochemical cell is used to replace the dissolved ozone that has reacted

    Galaxy and mass assembly (GAMA): The environmental impact on SFR and metallicity in galaxy groups

    Get PDF
    We present a study of the relationships and environmental dependencies between stellar mass, star formation rate, and gas metallicity for more than 700 galaxies in groups up to redshift 0.35 from the Galaxy And Mass Assembly (GAMA) survey. To identify the main drivers, our sample was analysed as a function of group-centric distance, projected galaxy number density, and stellar mass. By using control samples of more than 16 000 star-forming field galaxies and volume-limited samples, we find that the highest enhancement in SFR (0.3 dex) occurs in galaxies with the lowest local density. In contrast to previous work, our data show small enhancements of ∼0.1 dex in SFR for galaxies at the highest local densities or group-centric distances. Our data indicates quenching in SFR only for massive galaxies, suggesting that stellar mass might be the main driver of quenching processes for star forming galaxies. We can discard a morphological driven quenching, since the Sérsic index distribution for group and control galaxies are similar. The gas metallicity does not vary drastically. It increases ∼0.08 dex for galaxies at the highest local densities, and decreases for galaxies at the highest group-centric distances, in agreement with previous work. Altogether, the local density, rather than group-centric distance, shows the stronger impact in enhancing both, the SFR and gas metallicity. We applied the same methodology to galaxies from the IllustrisTNG simulations, and although we were able to reproduce the general observational trends, the differences between group and control samples only partially agree with the observations

    Numerical analysis of stream function, vorticity and circulation for a rotating flow with rigid boundary

    Get PDF
    En este trabajo se obtienen y analizan los campos de las funciones vorticidad tangencial, circulación y corriente meridional, que se generan en el interior de un cilindro cerrado que tiene el fondo giratorio y la tapa superior y envolvente sin movimiento. Los resultados se presentan mediante gráficas en las que se comparan dichas funciones, para un número de Reynolds de 3x10 4 y para un factor de forma (alto/radio) del recipiente de 0.5, 1.0 y 2.0. Se encontró al comparar el sistema con relación geométrica 2 respecto al 1, que la función corriente disminuye 29.63%; que la circulación permanece constante y que la vorticidad se reduce un 65.91%. Por otro lado, al comparar el sistema con relación geométrica 0.5 respecto al de 1, se encontró que la función corriente aumenta 1.4 veces, que la circulación se incrementó 3.45 veces y que la vorticidad aumentó 0.7 veces. Los resultados anteriores dan una idea del comportamiento de las funciones corriente, circulación y vorticidad tangencial para las relaciones geométricas antes mencionadas, pero se requiere de un mayor análisis para poder utilizar estos resultados al caso particular de mezclado o de alguna otra aplicación práctica de ingeniería.The tangential vorticity function, circulation and meridian stream that form in a closed rotating cylinder are analyzed. The cylinder has a rotating bottom whereas the lateral surface and the top are fixed. The results are presented as graphs that compare the mentioned functions for different aspect ratios. The comparing aspect ratios: 0.5, 1.0 and 2.0. In comparing the 2.0 aspect ratio versus the 1.0 aspect ratio; it is found that the stream function diminished a 29.63%, whereas the circulation does not change and the vorticity decreases 65.91%. On the other hand comparison of the cylinder with aspect ratio 0.5 against the one with aspect ratio 1; gives that the stream function increases 1.4 times; that the circulation increases 3.45 times and the vorticirty increases 0.7 times. The analysis was made for a 3 x 104 Reynolds number. The mentioned results give an indication of the influence of the aspect ratio as to the motion inside the cylinder. Further investigation is required in order to apply the results to particular conditions of mixing or another practical application.Peer Reviewe
    corecore